TY - JOUR
T1 - Radio pulse profile evolution of magnetar Swift J1818.0-1607
AU - Fisher, R
AU - Butterworth, EM
AU - Rajwade, KM
AU - Stappers, BW
AU - Desvignes, G
AU - Karuppusamy, R
AU - Kramer, M
AU - Liu, K
AU - Lyne, AG
AU - Mickaliger, MB
AU - Shaw, B
AU - Weltevrede, P
PY - 2024/2/1
Y1 - 2024/2/1
N2 - The shape and polarization properties of the radio pulse profiles of radio-loud magnetars provide a unique opportunity to investigate their magnetospheric properties. Gaussian process regression analysis was used to investigate the variation in the total intensity shape of the radio pulse profiles of the magnetar Swift J1818.0–1607. The observed profile shape was found to evolve through three modes between MJDs 59104 and 59365. The times at which these transitions occurred coincided with changes in the amplitude of modulations in the spin-down rate. The amount of linear and circular polarization was also found to vary significantly with time. Lomb–Scargle periodogram analysis of the spin-down rate revealed three possibly harmonically related frequencies. This could point to the magnetar experiencing seismic activity. However, no profile features exhibited significant periodicity, suggesting no simple correlations between the profile variability and fluctuations of the spin-down on shorter time-scales within the modes. Overall, this implies that the mode changes seen are a result of local magnetospheric changes, with other theories, such as precession, less able to explain these observations.
AB - The shape and polarization properties of the radio pulse profiles of radio-loud magnetars provide a unique opportunity to investigate their magnetospheric properties. Gaussian process regression analysis was used to investigate the variation in the total intensity shape of the radio pulse profiles of the magnetar Swift J1818.0–1607. The observed profile shape was found to evolve through three modes between MJDs 59104 and 59365. The times at which these transitions occurred coincided with changes in the amplitude of modulations in the spin-down rate. The amount of linear and circular polarization was also found to vary significantly with time. Lomb–Scargle periodogram analysis of the spin-down rate revealed three possibly harmonically related frequencies. This could point to the magnetar experiencing seismic activity. However, no profile features exhibited significant periodicity, suggesting no simple correlations between the profile variability and fluctuations of the spin-down on shorter time-scales within the modes. Overall, this implies that the mode changes seen are a result of local magnetospheric changes, with other theories, such as precession, less able to explain these observations.
KW - pulsars: individual: PSR J1818-1607
KW - Stars: magnetars
KW - Stars: neutron
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=pure_starter&SrcAuth=WosAPI&KeyUT=WOS:001168457100009&DestLinkType=FullRecord&DestApp=WOS_CPL
U2 - 10.1093/mnras/stae271
DO - 10.1093/mnras/stae271
M3 - Article
SN - 1365-2966
VL - 528
SP - 3833
EP - 3843
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -